Moving Picture Experts Group (MPEG or MP3) and Musical Instrument Digital Interface (MIDI) are protocols for digital audio storage and transmission.
MIDI was designed for the recording and playback of digital audio content on synthesizers. MIDI streams do not represent audio content directly but provide information about how the content is to be synthesized. MIDI streams are multi-track, where each track can be mapped to a discrete profile such as a musical instrument. Each track of the MIDI stream includes the discrete notes to be played by that instrument. Since a MIDI file is the computer equivalent of traditional sheet music for a particular song (figuratively speaking, as opposed to the sound recording for the song itself, these files tend to be small and compact when compared to files which record the audio content directly and continuously. However, MIDI streams typically require some form of wave table or FM synthesizer chip to generate their sounds. Additionally, MIDI files tend to lack the richness and robustness of actual sound recordings of the same content.
MP3 streams, unlike MIDI streams, contain actual sound recordings of audio content. Typically, MP3 streams are single track files and do not include information concerning the specific musical notes or the instruments utilized in the recording. However, while MIDI files typically require additional hardware in order to be played back, MP3 files can quite often be played back on a modem multimedia personal computer with a minimal amount of specialized hardware.